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Credential Schemas

When an ecosystem has created its Trust Registry in a VPR, it can create and manage credential schemas.

Here is the process for publishing a given credential schema, and make it usable by ecosystem participants:

  1. Ecosystem creates and configure a Credential Schema entry in a VPR, linked to its Trust Registry. Entry includes a JSON schema.
  2. Ecosystem issues, with its ecosystem DID, a verifiable trust JSON schema credential, which is a json schema credential linked to the JSON schema created in the VPR.
  3. Ecosystem presents, in its DID document the verifiable trust JSON schema credential as a linked verifiable presentation, and declares the VPR in a "service" section.

Then, authorized issuers can issue verifiable trust credentials linked to the verifiable trust JSON schema credential issued by ecosystem DID.

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note

Data stored in the VPR is not verified at the time of storage, nor does it need to be. Verification happens outside the scope of the VPR.

This is not a limitation, it’s a feature. For example, any DID method can be used, and the VPR will never attempt to resolve or validate DIDs itself.

The VPR provides registrations, not validations, leaving trust decisions and verification where they belong: with the relying parties.

1. Creating the Credential Schema Entry​

In a VPR, each created Credential Schema includes a JSON schema that defines the structure of its corresponding verifiable credential.

Here is an example of a JSON schema:

{
  "$id": "vpr:verana:mainnet/cs/v1/js/12345678",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "ExampleCredential",
  "description": "ExampleCredential using JsonSchema",
  "type": "object",
  "properties": {
    "credentialSubject": {
      "type": "object",
      "properties": {
        "id": {
          "type": "string",
          "format": "uri"
        },
        "firstName": {
          "type": "string",
          "minLength": 0,
          "maxLength": 256
        },
        "lastName": {
          "type": "string",
          "minLength": 1,
          "maxLength": 256
        },
        "expirationDate": {
          "type": "string",
          "format": "date"
        },
        "countryOfResidence": {
          "type": "string",
          "minLength": 2,
          "maxLength": 2
        }
      },
      "required": [
        "id",
        "lastName",
        "birthDate",
        "expirationDate",
        "countryOfResidence"
      ]
    }
  }
}

2. Creating the JSON Schema Credential​

Ecosystem issues, with its ecosystem DID, a verifiable trust JSON schema credential, which is a json schema credential linked to the JSON schema created in the VPR.

This credential serves as a verifiable proof of:

  • Ownership of the Credential Schema created in the VPR;
  • Control over the corresponding Trust Registry ecosystem DID.
{
  "@context": [
      "https://www.w3.org/ns/credentials/v2"
  ],
  "id": "https://ecosystem/shemas-example-jsc.json",
  "type": ["VerifiableCredential", "JsonSchemaCredential"],
  "issuer": "did:example:ecosystem",
  "issuanceDate": "2024-01-01T19:23:24Z",
  "credentialSchema": {
    "id": "https://www.w3.org/ns/credentials/json-schema/v2.json",
    "type": "JsonSchema",
    "digestSRI": "sha384-S57yQDg1MTzF56Oi9DbSQ14u7jBy0RDdx0YbeV7shwhCS88G8SCXeFq82PafhCrW"
  },
  "credentialSubject": {
    "id": "vpr:verana:mainnet/cs/v1/js/12345678",
    "type": "JsonSchema",
    "jsonSchema": {
      "$ref": "vpr:verana:mainnet/cs/v1/js/12345678"
    },
    "digestSRI": "sha384-ABCSGyugst67rs67rdbugsy0RDdx0YbeV7shwhCS88G8SCXeFq82PafhCeZ" 
  }
}

3. Updating the Ecosystem DID Document​

Finally, ecosystem presents, in its DID document, the verifiable trust JSON schema credential as a linked verifiable presentation, and declares the VPR in a "service" section.

This ensures that the credential schema and its controlling trust registry are publicly discoverable and cryptographically verifiable.

"service": [
    {
      "id": "did:example:ecosystem#vpr-schemas-example-jsc-vp",
      "type": "LinkedVerifiablePresentation",
      "serviceEndpoint": ["https://ecosystem/schemas-example-jsc-vp.json"]
    },
    {
      "id": "did:example:trust-registry#vpr-schemas-trust-registry-1234",
      "type": "VerifiablePublicRegistry",
      "version": "1.0",
      "serviceEndpoint": ["vpr:verana:mainnet"]
    }
    ...
  ]

Then, authorized issuers can issue verifiable trust credentials linked to the verifiable trust JSON Schema Credential issued by ecosystem DID.